6.2.1 Outline storage details with reference to blocking, sectors, cylinders
and heads.
Blocking Each Hard Drive Track is split into multiple blocks to decrease Seek time and Latency. Sector A group of blocks Cylinder A group of tracks on multiple platters which can be read/written to simulataneously. Head The magnetic end of the arm which reads and writes data to tracks.
Hard drive platters are thin disks made of glass or aluminium, covered with a layer of cobalt alloy which is magnetic.
Clustering- because of clustering data can be lost. For example: if clusters are set to 4kB and a 2kB file is written, 2kB of disk storage is lost.
6.2.2 Describe access time in terms of latency (rotational delay), seek time and transfer time.
Latency The time needed for the platter to spin itself to the correct block / sector Seek Time The time needed for the head arm to move to the correct track. Transfer time Time needed to transfer data from the hard drive to the RAM through the Logic board, cache and Hard Drive cables.
Logic Board
The logic board is an important piece of hardware which works as an interface between the computer and the disk drive. This is called the detection routine and serves to give the computer an idea of what the drive is, how big it is, what cable it uses and how to access it in the system OS. With a dead logic board, hard drive is not detected by OS.
The logic board also holds read / write cache which is crucial to the performance of hard disks. if you tell the computer to open 1000 mb of info, the hard drive passes the info ASAP. When the drive loads the first 16 MB, the next chunk of data is prepared. The cached chunk is prepared to roll as another is rolled into cache. The reverse of the process occurs when writing information too. The procedure ensures the data retrieval / archival is expedient overcomeing some of the limitations of a hard drive's sluggish mechanical design.
The logic board translates the computer's requests for archival retrieval into into the commands and make the hard dribe do its magic and read/write. Logic boards are more and more powerful processing units and more memory.
A Hard drive spins to access data - The rotational latency is the time taken for the hard drive read write head to move over useless data to the data you are trying to access.
A Typical Read / Write Cycle
1. User requests information.
2. Operating System accesses the MFT (Master File Table) cvia the motherboard's hard drive controller to find the file cluster.
3. Operating System tells the hard drive's logic board, via the
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6.2.1 Outline storage details with reference to blocking, sectors, cylinders
and heads.
Blocking Each Hard Drive Track is split into multiple blocks to decrease Seek time and Latency.
Sector A group of blocks
Cylinder A group of tracks on multiple platters which can be read/written to simulataneously.
Head The magnetic end of the arm which reads and writes data to tracks.
Hard drive platters are thin disks made of glass or aluminium, covered with a layer of cobalt alloy which is magnetic.
Clustering- because of clustering data can be lost. For example: if clusters are set to 4kB and a 2kB file is written, 2kB of disk storage is lost.
6.2.2 Describe access time in terms of latency (rotational delay), seek time and transfer time.
Latency The time needed for the platter to spin itself to the correct block / sector
Seek Time The time needed for the head arm to move to the correct track.
Transfer time Time needed to transfer data from the hard drive to the RAM through the Logic board, cache and Hard Drive cables.
Logic Board
The logic board is an important piece of hardware which works as an interface between the computer and the disk drive. This is called the detection routine and serves to give the computer an idea of what the drive is, how big it is, what cable it uses and how to access it in the system OS. With a dead logic board, hard drive is not detected by OS.
The logic board also holds read / write cache which is crucial to the performance of hard disks. if you tell the computer to open 1000 mb of info, the hard drive passes the info ASAP. When the drive loads the first 16 MB, the next chunk of data is prepared. The cached chunk is prepared to roll as another is rolled into cache. The reverse of the process occurs when writing information too. The procedure ensures the data retrieval / archival is expedient overcomeing some of the limitations of a hard drive's sluggish mechanical design.
The logic board translates the computer's requests for archival retrieval into into the commands and make the hard dribe do its magic and read/write. Logic boards are more and more powerful processing units and more memory.
A Hard drive spins to access data - The rotational latency is the time taken for the hard drive read write head to move over useless data to the data you are trying to access.
A Typical Read / Write Cycle
1. User requests information.
2. Operating System accesses the MFT (Master File Table) cvia the motherboard's hard drive controller to find the file cluster.
3. Operating System tells the hard drive's logic board, via the
Best content in StJulians_ComputerScience | Diigo - Groups